nl80211: Add API to support VHT MU-MIMO air sniffer

add API to support VHT MU-MIMO air sniffer.
in MU-MIMO there are parallel frames on the air while the HW
has only one RX.
add the capability to sniff one of the MU-MIMO parallel frames by
giving the sniffer additional information so it'll know which
of the parallel frames it shall follow.

Add attribute - NL80211_ATTR_MU_MIMO_GROUP_DATA - for getting
a MU-MIMO groupID in order to monitor packets from that group
using VHT MU-MIMO.
And add attribute -NL80211_ATTR_MU_MIMO_FOLLOW_ADDR - for passing
MAC address to monitor mode.
that option will be used by VHT MU-MIMO air sniffer to follow a
station according to it's MAC address using VHT MU-MIMO.

Signed-off-by: Aviya Erenfeld <aviya.erenfeld@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 7bbb00d..fa4f0f7 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -330,6 +330,9 @@
  * in a separate chapter.
  */
 
+#define VHT_MUMIMO_GROUPS_DATA_LEN (WLAN_MEMBERSHIP_LEN +\
+				    WLAN_USER_POSITION_LEN)
+
 /**
  * struct vif_params - describes virtual interface parameters
  * @use_4addr: use 4-address frames
@@ -339,10 +342,13 @@
  *	This feature is only fully supported by drivers that enable the
  *	%NL80211_FEATURE_MAC_ON_CREATE flag.  Others may support creating
  **	only p2p devices with specified MAC.
+ * @vht_mumimo_groups: MU-MIMO groupID. used for monitoring only
+ *	 packets belonging to that MU-MIMO groupID.
  */
 struct vif_params {
-       int use_4addr;
-       u8 macaddr[ETH_ALEN];
+	int use_4addr;
+	u8 macaddr[ETH_ALEN];
+	u8 vht_mumimo_groups[VHT_MUMIMO_GROUPS_DATA_LEN];
 };
 
 /**